1. Field of the Invention
The present invention relates to a method of setting a reference position of an actuator in an automated manual transmission, and more particularly, to a method of setting a reference position for the control of an actuator in an automated manual transmission, in which a speed change is carried out by a selection operation of selecting a shift rail, to which a target transmission gear is allocated, and a shifting operation of completing the speed change to the target transmission gear by displacing the selected shift rail, and the selection operation and the shifting operation are carried out using the actuator.
2. Description of Related Art
FIG. 1 shows a transmission mechanism of an automated manual transmission of the related art to which the present invention can be applied, specifically, a double clutch transmission.
Referring to FIG. 1, the transmission mechanism includes two fingers F which move up and down on the paper surface to carry out a selection operation and pivots to carry out a shifting operation, an odd stage selection actuator 9 and an even stage selection actuator 13 which respectively move the two fingers F up and down, and an odd stage shifting actuator 11 and an even stage shifting actuator 15 which respectively pivot the two fingers F. A speed change operation is carried out as desired in response to the two fingers F carrying out the selection operation by moving up and down and carrying out the shifting operation by moving to the right and left, as shown in FIG. 2.
The odd stage selection actuator 9 and the even stage selection actuator 13 are implemented as a solenoid actuator, and the odd stage shifting actuator 11 and the even stage shifting actuator 15 are implemented as a motor. The motor is characterized in that it requires additional position sensors in order to locate the position of the fingers F following its operation. However, the position sensors increase the price of a product and are disadvantageous considering the configuration and weight of a package. An approach that enables a controller to correctly locate the fingers F with no position sensors is required.
In the related art, the following method is used in order to locate the fingers. During startup of a vehicle, the fingers are set to specific reference positions. When the fingers are confirmed to be located at the specific reference positions, the subsequent rotation of the motor is calculated based on the reference positions in order to track and locate the position of the fingers.
For reference, the reference positions of the two fingers F are marked in FIG. 2. Since it is not guaranteed that the fingers F are located at the reference positions as shown during startup of the vehicle, an initialization operation of moving the fingers F to the reference positions must be carried out.
FIG. 3 shows a method of setting a reference position of a finger, i.e. an actuator, of the related art. During ignition of a vehicle, a finger F is moved in the shifting direction following the sequence of numbers shown in FIG. 3. Afterwards, the full stroke of the finger F is checked. When the full stroke satisfies a preset value, the finger F is moved to a position where selection is enabled. Here, selection is enabled when the finger is moved to a middle position. In sequence, the finger F is reciprocated in the selecting direction, so that a correct reference position of the finger F can be determined and set.
However, in the initialization process as described above, when baulking occurs, i.e. the full stroke that has been calculated by reciprocating the finger F in the shifting direction is less than the preset value, the above-described initialization cannot be completed.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.